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view xml/en/docs/http/ngx_http_limit_req_module.xml @ 1724:ce3e89d13fa0
Removed unneeded comma in "Since ..." Russian constructs.
author | Maxim Dounin <mdounin@mdounin.ru> |
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date | Tue, 07 Jun 2016 19:00:33 +0300 |
parents | 6c96a644b0b3 |
children | 469aebbd94d0 |
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<?xml version="1.0"?> <!-- Copyright (C) Igor Sysoev Copyright (C) Nginx, Inc. --> <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> <module name="Module ngx_http_limit_req_module" link="/en/docs/http/ngx_http_limit_req_module.html" lang="en" rev="6"> <section id="summary"> <para> The <literal>ngx_http_limit_req_module</literal> module (0.7.21) is used to limit the request processing rate per a defined key, in particular, the processing rate of requests coming from a single IP address. The limitation is done using the “leaky bucket” method. </para> </section> <section id="example" name="Example Configuration"> <para> <example> http { limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s; ... server { ... location /search/ { limit_req zone=one burst=5; } </example> </para> </section> <section id="directives" name="Directives"> <directive name="limit_req"> <syntax> <literal>zone</literal>=<value>name</value> [<literal>burst</literal>=<value>number</value>] [<literal>nodelay</literal>]</syntax> <default/> <context>http</context> <context>server</context> <context>location</context> <para> Sets the shared memory zone and the maximum burst size of requests. If the requests rate exceeds the rate configured for a zone, their processing is delayed such that requests are processed at a defined rate. Excessive requests are delayed until their number exceeds the maximum burst size in which case the request is terminated with an error <http-status code="503" text="Service Temporarily Unavailable"/>. By default, the maximum burst size is equal to zero. For example, the directives <example> limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s; server { location /search/ { limit_req zone=one burst=5; } </example> allow not more than 1 request per second at an average, with bursts not exceeding 5 requests. </para> <para> If delaying of excessive requests while requests are being limited is not desired, the parameter <literal>nodelay</literal> should be used: <example> limit_req zone=one burst=5 nodelay; </example> </para> <para> There could be several <literal>limit_req</literal> directives. For example, the following configuration will limit the processing rate of requests coming from a single IP address and, at the same time, the request processing rate by the virtual server: <example> limit_req_zone $binary_remote_addr zone=perip:10m rate=1r/s; limit_req_zone $server_name zone=perserver:10m rate=10r/s; server { ... limit_req zone=perip burst=5 nodelay; limit_req zone=perserver burst=10; } </example> </para> <para> These directives are inherited from the previous level if and only if there are no <literal>limit_req</literal> directives on the current level. </para> </directive> <directive name="limit_req_log_level"> <syntax> <literal>info</literal> | <literal>notice</literal> | <literal>warn</literal> | <literal>error</literal></syntax> <default>error</default> <context>http</context> <context>server</context> <context>location</context> <appeared-in>0.8.18</appeared-in> <para> Sets the desired logging level for cases when the server refuses to process requests due to rate exceeding, or delays request processing. Logging level for delays is one point less than for refusals; for example, if “<literal>limit_req_log_level notice</literal>” is specified, delays are logged with the <literal>info</literal> level. </para> </directive> <directive name="limit_req_status"> <syntax><value>code</value></syntax> <default>503</default> <context>http</context> <context>server</context> <context>location</context> <appeared-in>1.3.15</appeared-in> <para> Sets the status code to return in response to rejected requests. </para> </directive> <directive name="limit_req_zone"> <syntax> <value>key</value> <literal>zone</literal>=<value>name</value>:<value>size</value> <literal>rate</literal>=<value>rate</value></syntax> <default/> <context>http</context> <para> Sets parameters for a shared memory zone that will keep states for various keys. In particular, the state stores the current number of excessive requests. The <value>key</value> can contain text, variables, and their combination. Requests with an empty key value are not accounted. <note> Prior to version 1.7.6, a <value>key</value> could contain exactly one variable. </note> Usage example: <example> limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s; </example> </para> <para> Here, the states are kept in a 10 megabyte zone “one”, and an average request processing rate for this zone cannot exceed 1 request per second. </para> <para> A client IP address serves as a key. Note that instead of <var>$remote_addr</var>, the <var>$binary_remote_addr</var> variable is used here. The <var>$binary_remote_addr</var> variable’s size is always 4 bytes for IPv4 addresses or 16 bytes for IPv6 addresses. The stored state always occupies 64 bytes on 32-bit platforms and 128 bytes on 64-bit platforms. One megabyte zone can keep about 16 thousand 64-byte states or about 8 thousand 128-byte states. If the zone storage is exhausted, the server will return the <http-status code="503" text="Service Temporarily Unavailable"/> error to all further requests. </para> <para> The rate is specified in requests per second (r/s). If a rate of less than one request per second is desired, it is specified in request per minute (r/m). For example, half-request per second is 30r/m. </para> </directive> </section> </module>